Motor vehicles include a body defining an interior occupant compartment and seats arranged within the interior. Front seats include a seat part or seat bottom and a back part or seat back. The seat back can be pivoted around a swivel axis. Rear seats are arranged behind the front seats within the interior of the motor vehicle. The seat back of the front seats includes a support structure, which is fastened to or rests against an upholstery and a seat cover. In order to increase the lateral support far the seats, in particular for the front seats, lateral support parts in the form of a U-shaped frame or U-shaped strut made out of metal can be fastened to the support structure of the seat back by means of a welded joint. Such lateral support parts fastened to the support structure, in particular to vertical struts of the support structure of the seat back, increase the lateral support for individuals on the seat during cornering maneuvers and exposure to resultant lateral accelerations. Seats, in particular front seats, with the additional lateral support parts, are also referred to as sports seats. The vertical struts and U-shaped lateral support parts are joined together by means of a welded joint. A larger opening is present between the bracket- or U-shaped lateral support parts and the vertical struts of the support structure of the seat back. In the process of manufacturing the seat, the lateral support parts made out of metal are to be joined with seat by means of a welded joint in an initial phase of the manufacturing process. Seats with and without lateral support parts are here fabricated. Because the lateral support parts are already fastened by means of the welded joint in the initial phase of manufacturing the seat, an expensive warehousing of the seats both with and without lateral support parts is required, thereby increasing the costs for manufacturing the seats. Manufacturing the lateral support parts as U-shaped struts made out of metal is expensive, and the welded joint is also cost-intensive to fabricate.